The purpose of this Mentored Patient-Oriented Research Career Award (K23) is to provide the investigator with additional training in clinical research methods for the dietary treatment and prevention of obesity and cardiovascular risk factors. The investigator is proposing a 5-year program composed of didactic and seminar-based training in nutrition research methodology, and a substantial, multifaceted research project of high clinical relevance. As US obesity prevalence continues to rise, the USDA food pyramid has faced increasing criticism from mainstream nutrition researchers and the general public. A growing body of evidence now suggests that a high refined starch or high glycemic load diet can exacerbate hunger, weight gain, and heart disease risk factors, particularly in the setting of insulin resistance and obesity. Public interest in moderate and low carbohydrate diets has escalated during the past 5 years, and a question of major public health importance is whether the US dietary guidelines and USDA food pyramid should continue to promote a starch-based diet. A clinical trial of popular diets recently reported by the investigator has contributed significantly to this debate. The proposed project has the following 3 specific aims: 1) To evaluate the effectiveness of low starch and standard versions of the USDA food pyramid for' -year weight loss and cardiac risk factor reduction under realistic clinical conditions in 200 overweight subjects. Outcomes will include body weight and composition, specialized lipoprotein assays, glucose, insulin, Creactive protein, and endothelial function assessed by brachial artery ultrasound in a subset of subjects. 2) To verify the logistical feasibility and number of subjects required for a large, multicenter trial comparing low starch versus standard USDA food pyramids for weight loss and cardiac risk reduction. 3) To determine dietary adherence rates, predictors of adherence, and the relationship between adherence and outcomes. This research is essential in order to support and strengthen current US dietary policy.